PITX1-AS1 and gastric cancer: PVT1 was a single lncRNA with the optimal diagnostic performance for GC, with an AUC of 0.949 (95% CI: 0.922–0.976), SEN of 0.808, and SPE of 0.969, while PVT1 and C5orf66-AS1 were the most effective combination, with an AUC of 0.972 (95% CI: 0.951–0.992), SEN of 0.941, and SPE of 0.937.